1. Field of the Invention
The present invention relates to a robot mechanism for inspection of a live-line suspension insulator string, and more particularly to a robot mechanism that can precisely inspect defects of insulators in live-line conditions while moving along a suspension insulator string of a high voltage transmission line.
2. Description of the Related Art
Generally, an insulator is an insulating material used for supporting and connecting an electric line to an electric post or an iron tower. An insulator string is prepared by attaching several insulators on top of another.
Most insulators are made from glass, earthenware, porcelain, and the like, and have metallic components attached thereto by adhesives. Therefore, the insulator is likely to undergo a failure due to salt or dust stained on the surface of the insulator by long term use after installation thereof. Also, the insulator suffers deformation caused by temperature variation, chemical problems relating to acids or alkalis, environmental variations relating to sunlight, and the like.
Insulator strings are generally classified into two kinds of insulator string, i.e. a suspension insulator string and a tension insulator string. These insulator strings are used for ultra-high voltage transmission lines, extra-high voltage distribution lines, electrified railway tracts, low voltage distribution overhead lines, and the like.
Most conventional mechanisms for inspection of insulator strings are applied to the tension insulator string instead of the suspension insulator string. Further, the conventional mechanism for inspection of the tension insulator string is a heavy and large-size manual inspection mechanism which can be manually operated by means of a hot stick, or which can be lowered along the insulator string by the weight of the mechanism and is then lifted again by means of a rope.
In detection of a defective insulator, it is necessary for such a conventional manual inspection mechanism to measure only one property of the insulator. Further, since the insulators are suspended from an electric line through which a high voltage flows, an operator of the conventional manual inspection mechanism is often exposed to dangers and other severe problems.
On the other hand, although not designed for inspection of live-line insulators, there are robots for cleaning the insulators while moving along the live-line insulator string. However, since such a conventional robot employs a mechanism for cleaning upper and lower surfaces of the insulator and includes lots of components, it has a large size and a heavy weight. Furthermore, since the conventional robot is designed to contact two or more insulators in operation, it is not desirable in terms of insulation.